• Journal of Mechanical Science and Technology
• /
• v.15 no.7
• /
• pp.839-846
• /
• 2001

Some deep drawing characteristics at elevated temperatures were investigated for the SCPI steel sheets by using a Cr-coated die. For this investigation, six different temperatures between room temperature and 250$\^{C}$, and six different drawing ratios ranging from 2.4 to 2.9 were considered. As a result, the limiting drawing ratio, the maximum drawing force and the maximum drawing depth were found to be affected sensitively by temperature, and more stable through-thickness strain distribution was observed at elevated temperatures. Some experimental results compared favorably with theoretical results obtained by using the finite element method.

• Transactions of Materials Processing
• /
• v.4 no.4
• /
• pp.345-352
• /
• 1995

Warm deep drawing for optimum forming conditions to give the maximum drawing depth is investigated and compared with the results from experiments performed at room temperature. Experiments which draw square cups of STS 304 stainless steel sheet under the constant lubrication condition of teflon film are made both in a crank and hydraulic press for two kinds of specimens. The maximum drawing depth at warm forming condition reaches 1.4 times the drawing depth at room temperature in a crank press, whereas 1.6 times in a hydraulic press, and also more uniform distribution of thickness in case of warm deep drawn cup is observed. The effects of other factors on formability, such as forming temperature, speed of press and cooling of punch are examined and discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2000.10a
• /
• pp.162-167
• /
• 2000

The warm deep drawability in square cup drawing is investigated about a newly developed high-strength steel sheet with retained austenite which is transformed into martensite during forming. For this investigation, six steps of temperature ranges, from room temperature to $250^{\circ}C$, and five kinds of drawing ratio, from 2.2 to 2.6 were adopted. As a result the maximum drawing force and the maximum drawing depth were affected by the elevated temperatures, and the more stable thickness strain distribution was observed to the elevated temperatures. But blue shortness happened over $200^{\circ}C$. The FEM analysis using the LS-DYNA code is adopted to compare the experimental results with the analytical results for thickness strain distribution.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.63-70
• /
• 1999

Some deep drawing characteristics to the elevated temperatures were investigated for the SCP1 steel sheets by using the Cr-coated die. For this investigations six steps of temperature ranges from room temperature to 25$0^{\circ}C$ and six kinds of drawing ratio from 2.4 to 2.9 were adopted. As a result the limiting drawing ration maximum drawing force and the maximum drawing depth were sensitively affected by the elevated temperatures and the more stable thickness strain distribution was observed to the elevated temperatures, Some experimental results were compared with analytical results using the DYNA-3D code.

• Transactions of Materials Processing
• /
• v.9 no.2
• /
• pp.186-192
• /
• 2000

Some deep drawing characteristics to the elevated temperatures were investigated for the SCPI steel sheets by using the Cr-coated die. For this investigations, six steps of temperature ranges, from room temperature to 25$0^{\circ}C$, and six kinds of drawing ratio, from 2.4 to 2.9 were adopted. As a result, the limiting drawing ratio, maximum drawing force, and the maximum drawing depth were sensitively affected by the elevated temperatures, and the more stable thickness strain distribution was observed to the elevated temperatures. Some experimental results were compared with analytical results using the DYNA-3D code.

• Transactions of Materials Processing
• /
• v.8 no.3
• /
• pp.221-221
• /
• 1999

Warm deep drawability in a square cup drawing was investigated using a newly developed high-strength steel sheet with retained austenite that was transformed into martensite during formation. For this investigation, six different temperatures between room temperature and 250℃, and five different drawing ratios ranging from 2.2 to 2.6 were considered. The results showed that the maximum drawing force and the drawing depth were affected by the change in temperature, and a more stable thickness strain distribution was observed at elevated temperatures. However, blue shortness occurred at over 200℃. FEM analysis using the LS-DYNA code was used to compare the experimental results with the numerical results for the thickness strain distribution.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1995.03a
• /
• pp.178-185
• /
• 1995

Warm deep drawing for optimum forming conditions to give the maximum drawing depth is investigated and compared with the results at room temperature. Experiments which draw square cups of STS 304 stainless steel sheet under the constant lubrication condition of teflon film made both in a crank and hydrqulic press for two kinds of specimens . The maximum drawing depth at warm forming condition reaches 1.4 times the drawing depth at room temperature in a crank press, whereas 1.6 times in a hydrqulic press, and also more uniform distribution of thickness in case of warm deep drawn cup is observed. The effects of other factors on formability , such as forming temperature, speed of press and cooling of punch are examinnied and discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2000.10a
• /
• pp.168-173
• /
• 2000

The limiting drawing ratio (LDR) under uniform heating of blanks was measured at the various temperature ranges between 25 and $250^{\circ}C$ by using two different blank shapes, square and circular blanks, and six different blank sizes with the drawing ratios(DR) of 2.4 to 2.9. The galvannealed steel sheet (SCP3CM 60/60) of 0.7mm thickness was used. The LDR at warm forming condition reached 1.2 times of that at room temperature, and the maximum drawing depth reached 1.9 times. The higher temperature was adopted, the more stable and uniform thickness strain distribution was observed.

• Transactions of Materials Processing
• /
• v.11 no.5
• /
• pp.423-429
• /
• 2002

The limiting drawing ratio (LDR) under uniform heating of blanks was measured at the various temperature ranges between 25 and 25$0^{\circ}C$ by using two different blank shapes, square and circular blanks, and six different blank sizes with the drawing ratios(DR) of 2.4 to 2.9. The galvannealed steel sheet (SCP3CM 60/60) of 0.7mm thickness were used. The LDR at warm forming condition reached 1.2 times of that at room temperature, and the maximum drawing depth reached 1.9 times. The higher temperature was adopted, the more stable and uniform thickness strain distribution was observed. Some cases of the experimental results were compared with the analitical results using the commercial finite element method (FEM) code.

• Transactions of Materials Processing
• /
• v.8 no.2
• /
• pp.152-159
• /
• 1999

This study is to investigate the effects of warm deep drawing with aluminum sheets of A1050-H16 and A5020-H32 for improving deep drawability. Experiments for producing circular cups and square cups were carried out for various working conditions, such as forming temperature and blank shapes. The limit drawing ratio(LDR) of 2.63 in warm deep drawing of circular cups in case of A5020-H32 sheet, whereas LDR of 2.25 in case of A1050-H16, could be obtained and the former was 1.4 times higher than the value at room temperature. The maximum relative drawing depth for square cups of A5020-H32 material was also about 1.92 times deeper than the depth drawn at room temperature. The effects of blank shape and forming temperature on drawability as well as thickness distribution of drawn cups were examined and discussed.